The present invention relates to a signal converter and a control device, and in particular, a signal converter and a control device used for controlling a motor.
As a rotation angle sensor, a resolver that detects a rotation angle of a rotor based on fluctuations in a magnetic field caused by a rotation of the rotor has been known.
Japanese Unexamined Patent Application Publications No. H8-287173 and No. H8-35856 disclose methods in which: the phase of one of two-phase resolver signals obtained by one-phase excitation is shifted by 90° by a signal converter; the phase-shifted signal is combined with the other of the two-phase resolver signals; and the angle of the resolver is detected from the combined signal. Further, Japanese Unexamined Patent Application Publication No. 2004-347612 discloses a device that detects (i.e., determines), in the angle of a resolver, whether or not there is an abnormality in the angle detection.